Electronic equipment involving semiconductive devices are essential for many modern applications. The semiconductive device has experienced rapid growth. Technological advances in materials and design have produced generations of semiconductive devices where each generation has smaller and more complex circuits than the previous generation. In the course of advancement and innovation, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometric size (i.e., the smallest component that can be created using a fabrication process) has decreased. Such advances have increased the complexity of processing and manufacturing semiconductive devices.
Micro-electro mechanical system (MEMS) devices have been recently developed and are also commonly involved in electronic equipment. The MEMS device is micro-sized device, usually in a range from less than 1 micron to several millimeters in size. The MEMS device includes mechanical and electrical features formed by one or more semiconductor manufacturing processes. The MEMS device includes fabrication using semiconductive materials to form mechanical and electrical features. For many applications, MEMS device is electrically connected to external circuitry to form complete MEMS systems. Commonly, the connections are formed by wire bonding. The MEMS device may include a number of elements (e.g., stationary or movable elements) for achieving electro-mechanical functionality. MEMS devices are widely used in various applications. MEMS applications include pressure sensors, printer nozzles, or the like. Moreover, MEMS applications are extended to optical applications, such as movable mirrors, and radio frequency (RF) applications, such as RF switches or the like.
Conventionally, MEMS devices are bonded with opaque silicon substrate such that any optics application or optical observation is not allow. In addition, to do a failure analysis (FA) or additional device analysis, the de-cap process is needed and the de-cap process usually accompanies with particles. For example, the stiction phenomenon may recover during the de-cap process. As a result, these MEMS devices are capped by utilizing top transparent substrate, for example glass substrate, such that these devices in integrated chips can be easily monitored. Therefore, there is a continuous need to modify structure and manufacturing method of the MEMS devices in order to improve the device performance as well as reduce manufacturing cost and processing time.